Röle destekli OFDM tabanlı görünür ışık haberleşmeleri

In this study, a relay-assisted visible light communication (VLC) system where an intermediate light source cooperates with the main light source is investigated. Specifically, two light sources in an office space; one is the information source employed on the ceiling and the other one is a task light, are considered. The system uses DC biased optical orthogonal frequency division multiplexing (DCO-OFDM) where the task light performs relaying to assist the communication and operates in half-duplex (HD) mode for both amplify-and-forward (AF) and decode-and-forward (DF) relaying. The bit error rate (BER) performance of the relay-assisted VLC system is investigated and the performance is further optimized through optimal AC/DC power allocation under illumination constraints. The DC power allocation is determined by sharing the number of light emitting diode (LED) chips between the terminals to satisfy a desired luminance ratio. The AC power allocation decides the fraction of the information signal power to be consumed at the terminals in order to minimize the BER. Numerical results reveal that cooperation brings significant performance gains over direct transmission.